Dogs have cones that are receptive at 429 and 555 nm and are dichromats. All evidence suggests that the dog is dichromat with vision similar to a human who is red-green color blind.. Cats are weak trichromats. Feline cones peak at 450, 500 and 555 nm. They live in a world of fuzzy pastels

Dogs and cats appear to respond to the blue and yellow short-wave length colors the best, but appear to have trouble with green and red. Both are also rod-dominant animals. As rods do not function in daylight these animals are dependent on their few cones for spatial and temporal visual resolution, which probably means that their blue and yellow visual world is a fuzzy blue and yellow world. What appears red to us is simply dark to the dog and cat, and a part of the green spectrum is indistinguishable from white. Colors that would appear very rich to us are more pastel-like to the cat. The cat sees a green, grassy lawn as a whitish lawn, and a green rose-bush as a whitish bush with dark flowers.

<snip>

Acuity is 30 cycles per degree (cpd) for humans, 18 cpd for horses, 12 cpd for dogs and 6 cpd for cats. Acuity in dogs is 0.4 times that of people, 0.67 times that of horses, and 2 times that of cats. Acuity in cats is 0.2 times that of people, 0.33 times that of horses, and 0.5 times that of dogs. If normal human vision is 20/20, then that of the dog is 20/50, the horse 20/33, and that of the cat is 20/100.

If you're looking for the animal with the best average acuity of all three senses, it's probably going to be between dog and cat. Choosing between them is going to be difficult, I think. Offhand, I would guess that dogs have a better sense of smell, while cats may have better hearing. I am not sure by what margin each one might exceed the other in the respective senses. Although both have good visual acuity, they don't have much in the way of color vision.

Falcons have much better vision than either, I think, but have a very poor sense of smell, and I doubt that their hearing is exceptional. Turvey vultures have very good vision and a good sense of smell, but again hearing may not be at the level of a dog or a cat.

I think throught the animal kingdom there are organisms that have adapted different organs for different uses. Rabbits for instance have large ears and they rely heavily on them, this compensates for relatively poor eyesight and moderate smelling capabilities. Also, many animals use a highly developed sense of touch through their vibrisa (wiskers) that can detect the most minute vibration in the air or on the ground. So to ask a Q about which animal has the best of all worlds, is kind of loaded, as there are few that do have the best of everything. Varying degrees must be factored in. In all I would say wild animals have more acute senses than domesticated ones, however, I have no cites to back this up. That being said, I would think Hienas (sp?) and wolverines and tigers and lions would rank relatively high up on all senses being intuned to their respective environs.

Yes, it is generally going to be a trade-off. You are not going to find an animal that is among the very best in all three categories. The best on average are going to be found among the mammalian carnivores.

I'll guess that the turkey vulture is a good candidate. Most birds, many of which have excellent visual acuity, have little or no sense of smell. The turkey vulture is an exception, possessing an acute sense of smell which helps it locate carrion. It also has very good sight and hearing, more typical in a bird.

A hawk can pick out a moving mouse from 100s of meters away. A owl has eyes that operate incredibly well in low light (and has three sets of eyelids). A woodcock has essentially 360 field of vision. Which is better?

Individually, our senses are far outperformed by other members of the animal kingdom, but it wouldn't be surprising if our average of all three senses puts us over the top.

Our eyes are pretty good (though not nearly as good as a hawk's). Our hearing is OK, but nothing special. As far as smell goes, we are damn near "blind" compared to a dog or most other mammals. I don't think we're in the running.

But the point is that the shark has developed a sense of smell for just one molecule.

Blood.

Do you have any cite for that? I have heard of sharks being attracted by urine, faeces and other such things in reading about surviving shp wrecks, and so read the advice to throw such deitrus far away from a raft so as not to attract sharks to the raft.

As far as smell goes, we are damn near "blind" compared to a dog or most other mammals. I don't think we're in the running.

Can you prove that? I've heard speculation that our sense of smell actually isn't too bad, but because of our excellent sight (certainly as compared to most other mammals) we just don't use smell very often. Feynman once did some experiments with this, and found that with training, he was able to determine whether a book had been handled by a human, and by which human, by scent alone. Which is a lot better than most folks think our sense of smell is.

__________________
Time travels in divers paces with divers persons.
--As You Like It, III:ii:328

Can you prove that? I've heard speculation that our sense of smell actually isn't too bad, but because of our excellent sight (certainly as compared to most other mammals) we just don't use smell very often. Feynman once did some experiments with this, and found that with training, he was able to determine whether a book had been handled by a human, and by which human, by scent alone. Which is a lot better than most folks think our sense of smell is.

We may have better capabilities than is sometimes assumed, but they are still pathetic compared to many other mammals. We have only about 5-6 million olfactory receptors in our olfactory epithelium, while a dog has more than 200 million. (These were the most frequent figures given in the sites I checked, although one said humans have 40 million, while dogs have one billion - but all agreed that dogs have 30-40 times more receptors than humans do.)

According to Whack-a-mole's quote above, human visual acuity is about 2.5 times better than that of a dog. Based on the figures above it's reasonable to assume that a dog's sense of smell would be more than 30 times more acute than our own. So a dog's sense of smell is better than ours by a much greater ratio than our vision is better than theirs.